A diagnostic method for diagnosing post-manufacture modular add-on components coupled to a system at least includes: a) dynamically retrieving control system topology information not stored at the time of manufacture pertaining to a module chosen for a system graphical display; b) via each module, generating diagnostic information about the components of a module; c) dynamically retrieving module diagnostic information pertaining to a module chosen for a system graphical display; d) hierarchically displaying the component levels of the module chosen for graphical display; e) providing a link between the component levels; and f) indicating the diagnostic status of a displayed component level.